STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble), a detached piece or fragment of rock. The word is thus applied to the small fragments scattered in the ground or on roads, to the water-worn pebbles of the sea shore or river beds, and to the hewn, dressed or shaped rock used as a building material, with which this article deals. A qualifying word generally accompanies " stone " when the term is applied to pieces of rock cut to a particular size and shape and used for a specific purpose, e.g. " mill-stone," " hearth-stone," " grave-stone," &c. The term " precious stone " is used of those minerals which, from their beauty of colour, &c., their rarity, and some-times their hardness, are valued for their suitability for ornaments (see GEMs). The word is also often applied to many objects resembling a stone or pebble, such as the hard kernel of certain fruits, as of the cherry, plum, peach, &c., or the calculi or con-
Also called Janssen (Diet. Nat. Biog.), Jansen and Janson. Possibly he was the brother of the Gerard (Geraert) Jansen or John-son, of Southwark, who in 1616 executed the bust of Shakespeare in Stratford church; but it is uncertain whether the latter was identical with, or the son of, the Dutch tomb-maker Gerard Jansen described in Sir W. Dugdale's Diary as having, in 1593, lived for twenty-six years in England and as the father of five sons.cretions sometimes formed in the gall or urinary bladder or the
kidneys (see BLADDER DISEASES and KIDNEY DISEASES). The
" stone " has been a common measure of weight in north-western Europe. In Germany the " Stein" was of 20 to 22 lb. In the British system of weights the "legal" stone, or "horse-man's " weight is of 14 lb avoirdupois; in weighing wool it was also of 14 lb, but is now usually 16 lb. The " customary " stone for fish or butcher's meat is of 8 lb.
Building-stone.—In selecting a stone for building purposes many important points have to be considered. The stone must be strong enough to bear the load placed, upon it, it must be durable and weather well in the atmosphere of the district, and its colour and appearance need to be studied. It must further be ascertained whether a sufficient supply is available, and the price also must be taken into account; some difficulty is often experienced in obtaining a suitable stone at a moderate cost, and considerations of expense frequently have more to do with the choice of a stone than the architect would wish. Where there is risk of fire, as is often the case in business and factory premises, it is necessary to select a stone able to stand the effect of a great heat without damage. Great experience of the strength of stones and, of their behaviour in different situations is desirable; but even when this knowledge is given and the greatest care is combined with it, some point may be overlooked. For example, the stone facing of the Houses of Parliament at Westminster was chosen on the recommendation of a committee composed of men of eminent scientific and technical skill; yet it has not weathered
well because it is not constituted to resist the destroying effects of the London atmosphere.
The prime factor in the choice of a building stone should be the climate to which the material has to be exposed. Stone that in the pure country air has proved extremely durable Constttumay quickly decay in an impure city atmosphere, or
when subjected to the strong salt winds from the sea. tlOD• Extremes of temperature, too, are, generally speaking, prejudicial to the life of stone, the alternations of heat and cold setting up movements in the substances of the stone, which, though slight, will in many cases hasten its disintegration. There are few materials which more quickly decay and fail than stone placed under unsuitable conditions. An analysis, made by E. G. Clayton, of a sample of incrustation found on the Portland stone masonry of St Paul's Cathedral, London, gave the following result
Weight per cent. Water. (lost at loo°) . 2•o6
Water (lost at 150°) 22.48
Carbon (soot) 1•Io
Calcium sulphate 59'38
Calcium phosphate 2.22
Calcium silicate 1.63
Magnesium silicate o•67
Iron silicate 2.40
Sand and uncombined silica 8•o6

End of Article: STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)